scholarly journals A Coupled Eulerian-Lagrangian Simulation and Tool Optimization for Belt Punching Process with a Single Cutting Edge

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5406
Author(s):  
Dominik Wojtkowiak ◽  
Krzysztof Talaśka ◽  
Dominik Wilczyński ◽  
Jan Górecki ◽  
Krzysztof Wałęsa

The objective of this paper is to analyze the belt punching process with the use of a single cutting edge and discuss the influence of geometrical features of the piercing punch on the perforation force. Two basic shapes of the piercing punch with a single cutting edge were tested: tools with the blade pointing inside or pointing outside. The analytical models of the stress distribution in the shearing cross sections were derived for both punches. The presented model, along with the series of empirical tests and Coupled Eulerian-Lagrangian simulation, was used for finding the effective geometry of the piercing punch with a single cutting edge for the belt perforation. The geometrical parameters taken into consideration for the tool optimization were the following: angle of the blade, thickness of the wall and diameter of the piercing punch cutting edge. The obtained results show that changing these parameters has a significant influence on the perforation force necessary to execute the machining process and affects the quality of the holes in the perforated belts. The most important geometrical features of the hollow sharpened punch are the angle and the direction of the blade, which change the force distribution and, as a result, the mechanics of the process.

2018 ◽  
Vol 8 (8) ◽  
pp. 1353
Author(s):  
Tao Chen ◽  
Fei Gao ◽  
Suyan Li ◽  
Xianli Liu

Carbon fiber reinforced plastic (CFRP) is typically hard to process, because it is easy for it to generate processing damage such as burrs, tears, delamination, and so on in the machining process. Consequently, this restricts its wide spread application. This paper conducted a comparative experiment on the cutting performance of the two different-structure milling cutters, with a helical staggered edge and a rhombic edge, in milling carbon fiber composites; analyzed the wear morphologies of the two cutting tools; and thus acquired the effect of the tool structure on the machined surface quality and cutting force. The results indicated that in the whole cutting, the rhombic milling cutter with a segmented cutting edge showed better wear resistance and a more stable machined surface quality. It was not until a large area of coating shedding occurred, along with chip clogging, that the surface quality decreased significantly. At the stage of coating wear, the helical staggered milling cutter with an alternately arranged continuous cutting edge showed better machined surface quality, but when the coating fell off, its machined surface quality began to reveal damage such as groove, tear, and fiber pullout. Meanwhile, burrs occurred at the edge and the cutting force obviously increased. By contrast, for the rhombic milling cutter, both the surface roughness and cutting force increased relatively slowly.


2021 ◽  
Vol 111 (11-12) ◽  
pp. 803-806
Author(s):  
Dominik Hasselder ◽  
Eckart Uhlmann

Bei Drehbearbeitung auftretender Verschleiß am Werkzeug ist seit Jahrzehnten Gegenstand der Forschung, denn er beeinflusst die Oberflächengüte und den resultierenden Durchmesser des Werkstücks. Durch die gezielte Platzierung eines Triangulationssensors lassen sich Einflüsse dieser Art detektieren. In Zerspanungsuntersuchungen bei der Bearbeitung des austenitischen Stahls 1.4301 ohne Kühlmedium konnte gezeigt werden, dass der verschleißbedingte Durchmesserfehler und die hergestellte Oberflächentopografie prozesssicher messbar sind.   Tool wear and its detection has been part of academic research for decades. It may result in varying surface quality and is a potential cause of insufficient nominal diameter in turning. Mounting a triangulation laser on a turning tool allows for detecting variations in geometrical parameters of the workpiece. Also, when dry turning the austenitic steel 1.4301 it is possible to continuously detect the resulting surface topography and the discrepancy in the manufactured diameter.


2018 ◽  
Vol 108 (10) ◽  
pp. 736-742
Author(s):  
J. Hartig ◽  
B. Kirsch ◽  
J. Aurich

Mit Schneidkantenpräparation kann das Werkzeug im Zerspanprozess an die Bearbeitungsaufgabe angepasst werden. Homogene Präparationen können dabei entweder auf hohe Belastungen des Werkzeugs oder ein optimiertes Bearbeitungsergebnis im Sinne der Oberfläche ausgelegt werden. In diesem Beitrag wurden die Schneidkanten von Hartmetall-Wendeschneidplatten unterschiedlich inhomogen präpariert, um den unterschiedlichen Anforderungen entlang des Eingriffs Rechnung zu tragen. Neben der Werkzeugstandzeit wurde das Prozessergebnis beim Außenlängs-Runddrehen von ausferritischem Gusseisen (ADI) 900 untersucht.   The preparation of cutting edges allows for tools to be tailored to the machining process. A homogeneous preparation can either be designed for high loads in the machining process or an optimized machining result on the surface. In this article, the cutting edges of tungsten carbide indexable inserts were prepared inhomogeneously and thus individually matched to the machining task. Tool life and machining performance while turning austempered ductile iron (ADI) 900 were investigated.


2017 ◽  
Vol 12 (1) ◽  
pp. 45-51 ◽  
Author(s):  
E. Krebs ◽  
M. Wolf ◽  
D. Biermann ◽  
W. Tillmann ◽  
D. Stangier

Author(s):  
Norbert Kockmann ◽  
Michael Engler ◽  
Claus Fo¨ll ◽  
Peter Woias

Micro mixers are an integral part of several micro fluidic devices like micro reactors or analytical equipment. Due to the small dimensions, laminar flow is expected a priori in those devices while the mass transfer is supposed to be dominated by diffusion. A detailed numerical CFD-study by CFDRC-ACE+ of simple static mixers shows a significant deviation from strictly laminar flow in a wide range of Reynolds numbers Re, channel dimensions, and types of cross sections (square, rectangular, trapezoidal). With increasing flow velocity and Re number the flow starts to form vortexes at the entrance of the mixing channel. The vortexes are symmetrical to the symmetry planes of the mixing channel, both for the rectangular and the trapezoidal cross sections investigated here. With further increasing velocity the flow tends to instabilities, which causes a breakup of the flow symmetry. These instabilities are generally found in T-shape mixers with symmetrical flow conditions, but not always in Y-shape mixers or with asymmetrical flow conditions. Within the laminar flow regime diffusive mass transfer is dominant. In this case the mixing quality at constant channel length becomes worse with increasing velocity. This effect can almost be equalized by the onset of the vortex regime, which enhances the mass transfer by convective transport. This paper shows the mixing quality at a certain length for different geometrical parameters and flow conditions.


Author(s):  
Ehsan Sadeghi ◽  
Majid Bahrami ◽  
Ned Djilali

In many practical instances such as basic design, parametric study, and optimization analysis of thermal systems, it is often very convenient to have closed form relations to obtain the trends and a reasonable estimate of the Nusselt number. However, finding exact solutions for many practical singly-connected cross-sections, such as trapezoidal microchannels, is complex. In the present study, the square root of cross-sectional area is proposed as the characteristic length scale for Nusselt number. Using analytical solutions of rectangular, elliptical, and triangular ducts, a compact model for estimation of Nusselt number of fully-developed, laminar flow in microchannels of arbitrary cross-sections with “H1” boundary condition (constant axial wall heat flux with constant peripheral wall temperature) is developed. The proposed model is only a function of geometrical parameters of the cross-section, i.e., area, perimeter, and polar moment of inertia. The present model is verified against analytical and numerical solutions for a wide variety of cross-sections with a maximum difference on the order of 9%.


Author(s):  
L. Goteti ◽  
J. Choi ◽  
J. Park

Snap-fit integral attachments are used widely for joining plastic parts. The proliferated use of integral attachment in the form of snap-fit features in designs is due to the ability to mould such parts of great complexity at little cost. The exceptional diversity of part geometry and integral snap-fit features has made it seem that design possibilities may be unlimited. Thus, attempts at optimization might be intractable. A design of experiments (DOE) approach coupled with three-dimensional, geometrical non-linear finite element analysis (FEA) was used to calculate the insertion and retention responses on such parts for various geometrical parameters like length, width and angles. A statistical technique was employed to formulate empirical relationships among the geometrical dimensions, to investigate the effect of these parameters on the design as well as to obtain optimal insertion and retention forces or strains. Design equations obtained from this methodology were verified within the DOE domain and it was observed that the predicted responses were ranged within 30% of the FEA results. During this investigation, it was observed that geometrical features of a block, which exert force on the snap-fit features, have a considerable effect on the results. Therefore, the effects of the block parameters on the various responses were also studied. An attempt was also made to understand the effect of the block parameters such as corner radius and thickness on the design formula, which depicts the geometrical parameters of the snap-fit part as a function of insertion and retention forces. It is expected that the results help to find optimal design parameters in order to enhance the performance of such snap-fit features.


1968 ◽  
Vol 46 (23) ◽  
pp. 2645-2657 ◽  
Author(s):  
T. Y. Li ◽  
S. K. Mark

Elastic scattering cross sections for the interaction of 100-MeV protons with 6Li, 7Li, 9Be, and 12C have been analyzed using the optical model. The experimental differential cross sections are reasonably reproduced. It has been found that no average set of geometrical parameters can provide a quantitative fit to the experimental data for all of these light nuclei; they must be treated individually, with optimum optical potential parameters fluctuating from one nucleus to another. Other features revealed in this analysis include: (1) the spin–orbit radius parameter is smaller than those of the real and imaginary parts of the potential, (2) surface and volume absorption potentials give equally good fit to the experimental results, (3) the radius parameters of the real and imaginary potentials differed from each other, and (4) the radius parameter of the real part of the potential is larger than those used for heavy nuclei.


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